'''字典的操作'''
#不可变类型，String tuple None可以作为字典的key，只有这样才能保证计算出hashcode
#是不变的，hashcode最终决定了再内存中的存储位置。
L = [3,6,2]
t = (45,22,7)
d = {None:"guodegang"}

d = {"name":"于谦","age":30,"addr":"天津","job":"演员"}
print(len(d))#4
print(d.keys())
print(d.values())
print(d.items())#



